Ore roasting and smelting furnace



2 Sheets-,Sheet 1. J. J. STORBR.

Patented Mar. 20-l 1894. E

we NArluNAL LrmoaRAPmNa caMPANv.

WASHINGTON. lA a ORE ROAS'IING AND SMBLTING ]L'URNAGE.

(No Model.)

STATES ATENT rricn.

JACOB J. STORER, OFHELENA, MONTANA, ASSIGNOR TO THE UNITED MILL ANDFURNACE COMPANY, OF MONTANA.

ORE ROASTING AND SMELTING FURNACE.

SPECIFICATION forming part of Letters Patent No. 516,662, dated March20, 1894.

'Application filed March 8, 1893. Serial No. 45,216. (No model.)

To @ZZ whom it may concern:

Be it known that I, JACOB .I. STORER, of Helena, county of Lewis andClarke, and State of Montana, have invented certain new and usefulImprovements in Ore Roasting and Smelting Furnaces, of which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawings, and to the letters of reference markedthereon.

This invention is designed as an improvement on those so-called dryhearth ore-roasting or smelting furnaces, in which the raw ore isintroduced in a pulverized condition from above.

Its object is to provide an improved furnace for the complete reduction,by the dry method, of gold, silver, and other metallic ores; or fortheir preparation for subsequent treatment by amalgamation,chlorination, lixiviation, leaching, and other processes. Y

For the most thorough and economical treatment of ores in this furnace,they are first reduced to an exceedingly fine powder, about nine-tenthsof which will pass through a hundred mesh screen, and the balancethrough an eighty mesh. In its brief passage down the heated shaft eachminute ore particle will be aected as desired by the combined action ofheat, oxygen, carbon and other chemical reagents that may be introducedwith them: the completeness of the operation,the desulphurization,chlorination, the reduction of the oxides and the volatilization of thevolatile elements of the ore in the shaft,-being best assured by thelineness to which the ore and said re-agents are reduced.

To these ends the invention consists mainly of a dry hearth, reservoiror furnace of novel construction, set directly beneath and communicatingat its top with an upright, cylindrical, ore-feeding and desulphurizingshaft, which expands from above downward, and has about its top oppositefire places, between which is a space forming a gas-expansion chamber;said shaft, its replaces vand oxpansion chamber being designed for thetreatment of air-borne particles of -ore introduced at its top, -so thatthey shall fall hot and oxi' dized upon or into the receiving hearthor.`

furnace; all of Which Will be hereinafter fully set forth, and thendefinitely claimed.

Reference is to be had to the accompanying drawings, forming part ofthis specification, in whichsimilar letters of reference indicate 5 5corresponding parts. Figure 1 represents a longitudinal, sectionalelevation of my improved device, showin g one form of the receivinghearth, reservoir or furnace. Fig. 2 represents a vertical section on 6oline X X Fig. l, as indicated by an arrow. Fig. 3 represents alongitudinal, sectional elevation, showing another form ofthe receivinghearth,reservoir or furnace. Fig. 4 represents a horizontal section online YY Fig. 3.

In the drawings A represents the ore-feeding shaft, preferably ofcylindrical cross section, and expanding from above downward. Thisshaft, which extends downward from the roofs of the fire places,consists of an exterior 7o wall a., and an interior wall b, betweenwhich is an annular air space c, which is, preferably,- closed at bothtop and bottom. About the top of this shaft, and constructed so as tointernally communicate with it, are one or more lire places D (fourherein shown), directly 0pposite each other, so constructed with slopinggrates d, and slooping roofs f, that the heat therefrom shall beradiated through their throats, as indicated byarrows, directly into 8othe vertical vaxis ofthe shaft, or rather into the axis of thegas-'expansion chamber D2 which is formed in the top of the shaft by thewide open throats of the fire places. Openings f', that may be closed byStoppers or 85 doors f2, are for feeding fuel into these fire places.

In the roofs of the fire places are fixed stove pipes E, provided withdampers f3, whichl pipes serve to carry off the smoke'and gases, 9o andturn-ish temporary draft, when the fires are rst lighted. A cylindricalpipe or conductor F, preferably of brick, is fixed centrally above andbetween the fire places, with its vertical axis corresponding with thatof the shaft A. The ore to be treated is, after being finely pulverized,fed down this conductor F, into the heated shaft A, being introducedinto said conductor on an air current from a fan blower or throughasieve (not roo shown). If it be an ore containing sufficient sulphurfor maintaining by its combustion a proper temperature, it will, ifsufficient air be admitted with it, become thoroughly desulphurized bythe combined action of the heat and oxygen, before reaching the dryhearth, reservoir or furnace G, which is constructed beneath the shaftA, as shown. If it be an oxide ore, or one containing but a small amountof sulphur, pulverized coal maybe introduced with it, so that, by itscombustion, the proper temperature may be maintained in the shaft A; thedesired temperature being between a dull, red and a white heat,according to the character of the ore to be treated. If salt beintroduced down the heated shaft, finely pulverized and mixed with theore, the latter will he brought into the best condition for subsequentchlorination, amalgamatiomor leaching withsuitable chemical solutionsfor the purpose of obtaining the precious metals it may contain.The'ore, as it accumlates in the dry hearth or furnace (of the formshown in Figs. l and 2) may be drawn out through the door I-I.

Just beyond the outer wall of the shaft A, and in the roof of thehorizontal flue I, is shown a hood plate or damper K, so arranged as toslide up or down in suitable guides, not shown, to diminish or increasethe area of the throat of said dry hearth, as may be desired, as shownby dottedlines. By fixing this hood as shown by full lines, a narrowopening or throat is left between its lower edge and the bridge wall L,so that, if desired, the hot air and gases from the shaft A, beingthereby retarded and retained in the dry hearth, reservoir or furnace,may operate to bring the mass of ore therein deposited to a highertemperature. This hood or damper serves the additional purpose ofretaining much of the ore in the dry hearth that would otherwise passthrough into the flue, for many of the smaller particles of ore thatwould otherwise pass through would strike against the hood or damper andrebound back into the hearth. The damper thus serves not only as anordinary damper, but it has the additional function above described. Thegases generated by the combustion of the ore constituents, and of theintroduced fuel if there be any, together with some of the finest `oredust, will pass out through the furnace or dry hearth into the smokeiiue I, where they will be partially wet down and condensed by watersprays issuing from the water pipes N, as indicated in Fig. l, andfaliupon the sloping bottom of said flue, and flow off through a pipe1.2,intoasuitable reservoir (not shown) for further treatment.` Theresidue of the dust and gases will pass on through an opening oropenings s in the end wall of the flue I, into the spray wheel chamberO, where it is wetted down by the action of the draft and spray wheel R,which, when in operation, causes the downward draft of the hot air andames from the tire places at the top of the shaft A, and of the oreintroduced into said shaft. Water, or water with the proper chemicalreagents in suspension or solution, in sufficient quantity for theproduction of the requisite amount of spray, is introduced upon thespray wheel through the pipe n, and this spray with the absorbed gasesand dust, is thrown by the wheel R, upon and through the cob or latticework Q, which iills the base of the smoke stack R', and thence drains0E, through a pipe QJ, into a suitable reservoir,not shown. This latticeor cob work Q, may be made of any dimension desired, if the combinedareas of the openings are fully sufficient for the free upward passageof the air to be expelled through them. Itsgreat value lies in theextensive condensing and arresting surface which it presents to theescaping steam, Water-spray, gases and dust.

In Fig. 3 is shown another form of dry hearth, reservoir or furnacecovered by this invention. In this case the bottom of the dry hearth orfurnace G, instead of being fiat, as

vshown in Figs. l and 2, is made concave or bowl-shaped, as shown, forthe purpose of holding the molten metal when extracted from the ore.This form of hearth or furnace is adapted for smelting or matting; andfor this purpose, it is made of greater area, that it may hold a muchlarger amount of ore than the furnace shown in Fig. 1, and its sidewalls are outwardly curved, as shown in Fig. 4, so that it is, ineffect, a reverberatory furnace; and, that it and the ore falling intoit may be heated to any desirable temperature for the fusion of the oreand the separation of the metal from the gangue, an auxiliary fire-placeY, is constructed in the rear, to furnish additional heat, andpreferably pulverized fuel may be introduced by means of a fan orpulverizer, as indicated at X, through an opening or tuyere t, in therear wall of the furnace, over the throat of this lire-place, so that itwill there ignite and burn over the mass of ore in the furnace bottom.But the fire-place Y may be made of suiiicient dimensions to furnish therequired heat to the furnace.

In order to prepare this smelting hearth or furnace for the reception ofthe ore into it from above, a tire is made in the auxiliary tire-'placeY, and urged until it is sufficiently hot to set [ire to the pulverizedfuel that may be introduced over it; then the hood plate K, which, inthis instance, may be made to serve as a damper, is lowered, asindicated by dotted lines, Fig. 3, to close the throat of the fur nace;then the pulverized coal, mingled with air sufficient for itscombustion, is introduced over the throat of the auxiliary fireplaceinto the furnace by means of the fan'or pulverizer above referred to,and is there consumed with intense heat, while a portion of the flameand gaseous products of combustion ascend the shaft A, and escapethrough the conductor F, and the re place pipes E. Thus in a Very shorttime the temperature of this furnace can be raised throughout to the oremelting IOO wheel is set in motion, and the introduction` ofthe orethrough the conducting pipe F, is begun, while the air-borne, pulverizedfuel is still fed horizontally into the furnace by the fan orpulverizer. The line particles of airborne ore falling down the heatedshaft, and becoming therebydesulphurized and oxidized,

pass through the horizontal sheet of the car-.

bonizing and deoxidizing flame and gases of the pulverized fuel,entering through the tuyore t, which instantly reduce the bulk of theoxides to metals that fall with the gangue into the bottom of hearth orfurnace, where they both-accumulate in a molten condition. Because ofits less specific gravity the molten gangue or slag floats on the top ofthe molten metal, and what unreduced oxides the slag may contain arereduced by the deoxidizing ame in the furnace and then sink through theliquid slag into the metal bath below. It is found that when the ore isreduced to suficient Iineness, all the sulphur is eliminated from it inits brief passage of one or two seconds down the heated shaft A, andthat hence no sulphidesreach the hearth to retard the reduction of themetals. When it is desired to tap out the melted slag and metal, thefeed-v ing in of the ore is suspended, and when this operation is overthe feeding of the ore is resumed as before. What re-agents or fluxesare necessary in working the ores may be laid upon the hearth in theform of grouting,may be spread upon the surface of the charge in thefurnace through suitable doors, not shown, may be introduced down theshaft with the raw ore, or may be introduced with the pulverized fuel.The exit or smoke iiue leading to thespray Wheel hasinit severalperforated walls Z, constructed of brick or tile, or otheracid-resisting material, .laid with wide spaces through them for thepassage of the furnace gases; and these walls being constantly wettedand cooled by Water from the pipe N, serve to cool and condense' thegreater portion of the escaping gases, smoke and metallic fumes, and toarrest most of the ore dust from the volume passing on to the. spraywheel, where the residue is wetted down.

I am aware that water sprays, perforated walls kept wet with water, andjets of steam, have long been used for arresting and condensing thegases, dust and metallic fumes in the lues of ore-roasting furnaces. Butso far as known, the effect of these separately. or in combination isonly partial, for the resulting steam or mist escaping from the furnaceflues is found in all cases to contain a very appreciable amount ofmetallic dust. In order to prevent this loss, and to prevent theinjurious eects upon the surrounding vegetation from this dust deposit,I have combined with these usual condensing devices an exhaust fan andspray Wheel, upon which coldwater alone, or water, holding chemicalAreagents, such as chloride of lime, quick lime, carbonate of soda,chloride of sodium, chloride of potassium, and such other re-agents asmay be advantageous in treating any special ores, is introduced, to beconverted into a fine spray and he thrown forward upon and into a pileof cob or lattice work which may partly or completely fill the smokestack. This draft and spray wheel may be made of any desired dimensionsand be run at any required speed, and any required supply of water orchemical solution may be introduced upon said wheel, while the pile ofcob or lattice work may easily be of such dimensions as to present anabsolutely eective condensing surface. Hence it is obvious that thisimproved, combination, condensing device must eect the desiredresults.

The devices for condensing the fumes herein shown but not claimed willbe found shown and claimed in an application of mine bearing the SerialNo. 483,475, and filed August 18, 1893.

Having thus described my invention, I

claim as new and desire to secure by Letters Patentl. An ore roasting,smelting or matting furnace constructed substantially as herein shownand described, with an uprightorefeeding and desulphurizing shaft,expanding -from above downward, having about its top opposite re placeswith a gas expansion chamber between them, each fire-place having asloping grate and sloping back wall andconstructed to deiiect andradiate the heat therefrom directlyinto said combustion chamber anore-receiving dry hearth or furnace at the bottom of said shaft, and, atthe top, com,

municating with it; and a flue leading from the exit or throat of saiddry hearth or furnace to a smoke stack; as and for the purposes setforth.

2. An ore roasting, smelting or matting furnace constructedsubstantially as herein shown and described, with an upright ore feedingand desulphurizing shaft having opposite tire places about its top, agas expansion chamber between them, a reverberatory dry hearth orfurnace at the bottom of said shaft and at its top communicating withit; an auxiliary re place connected with said reverberatory furnace anda flue extending from the exit of said furnace for the escape of thegases therefrom, as set forth.

3. An ore roasting, smelting or matting furnace, constructedsubstantially as herein shown and described with an upright ore feedingand roasting shaft having lire places about its top; a reverberatory dryhearth or furnaceat the bottom of said shaft andpat its topcommunicating with it; an auxiliary tire f place connected with saidreverberatory furnace, the rear wall of said reverberatory furnace beingprovided with an opening or tuyere for the introduction of air-borne,pulverized fuel, substantially as set forth.

4. The combination with the upright shaft, the hearth or furnace at thebottom thereof, and with the flue leading from the exit of said hearthor furnace, of an adjustable damper, substantially as herein shown anddescribed; said damper being designed for adjusting or closing thefurnace throat or exit, as set forth.

5. A11 ore roasting, smelting or matting furnace constructedsubstantially as herein shown and described, With a vertical,cylindrical shaft, expanding from above downward and forming a freepassage, being interiorly devoid of shelves, inclined planes, or otherore-arresting devices, terminating in a reverberatory hearth or furnace,said shaft

